Check out this thread:
PhelsumaWeb.nl • Toon onderwerp - Breeding Phelsuma guimbeaui guimbeaui males
There are a number of renowned hobbyists sharing their experiences on that thread. I have learned a lot from some of the people on there. Depending on what the ratios I am trying to obtain and which species, I vary the incubation temperature.
For males, I incubate at baseline temperatures of 30 C. This attempts to replicate, in captivity, the average, seasonal
maximum temperatures of many of the islands where some of our species of interest are endemic to (Reunion, Mauritius, etc.) I say baseline because I implement occasional spikes up to 32 C. I do that on either exceedingly warm days here or down there, compensating for the fact that we are in two different hemispheres. I believe it is important to have varying daytime temperatures in the high range.
Incubator(s) shut off at night and temperature will drop to 18.5-22.5 C (it can get below 16 C during the cool season on some of these islands' mountain regions). I like having the incubator (s) on a timer as the temperature inside gradually warms and cools each day.
Incubating at very high temperatures does appear to increase mortality, even in eggs that hatch. For example, I had a clutch of borbonica that incubated near the higher thresholds of the range. Both hatched, but one only survived a few weeks and did not appear to thrive from the beginning. It could have been from something else, though. The survivor is male. The next clutch was incubated a bit cooler, both survived, and the ratio is 1.1. I had similar results with cepediana in an early clutch from last year. One hatchling emerged and thrives, the next one never hatched and was dried up, fully formed, in the egg.
All that said, I think there was increased mortality in clutches that had more days at or above 32 C. Lower spike temps near 31 C yielded the 1.1. Far better to have mixed sexes hatching and living than a reduced number of males hatching and living. I will be keeping better records this year and I think that is the ever important piece for all of us. We need to track this information precisely and then our methods get better.
I believe the more similarly we keep Phelsuma to their natural habitat and "preferences," the more success we will have. As keepers, do we know their natural temperature ranges, humidity, precipitation, etc.? I believe Mark had good ratios with guimbeaui last year resulting from good husbandry and local conditions. I can't wait to see how the cepediana do in those conditions.
